V/F Co-Doped Tno Anode Enables Superior High-Power and Long-Life All Solid State Lithium Batteries

Abstract

All solid state batteries (ASSBs) have garnered significant attention for safety and energy density. However, issues like poor redox stability of solid state electrolytes and electrode volumetric expansion during charge-discharge cycles lead to severe interfacial problems and accelerated battery degradation. TiNb2O7 (TNO), a promising anode material, has a high reaction potential and low strain performance, which can reduce interfacial reactions and mechanical stress, preventing contact failure. In this study, V/F co-doped TNO (V/F-TNO) shows excellent electrochemical performance, with a reversible capacity of 322.8 mAh g−1 at 0.1 C and 78.2% capacity retention after 1500 cycles at 10 C. In LiCoO2|Li6PS5Cl|V/F-TNO ASSBs, it exhibits superior rate capability, delivering 119.5 mAh g−1 at 4 C and 60 °C. Even under the extreme condition of 100 °C, it can continuously charge/discharge at 40 C, achieving 86.4 mAh g−1. It also has high-capacity retention of 95.5% after 100 cycles at 0.1 C and 25 °C. The corresponding pouch cell has a discharge specific capacity of 178.3 mAh g−1 and an initial efficiency of 81%. This research offers an effective strategy for developing high-rate and long-life TNO anodes for ASSBs, highlighting its potential for high-performance energy storage applications.

Keywords: TiNb2O7, V5+/F- co-doping, Low-strain anode, conductivity, All solid state battery